[Radiotherapy for intracranial meningioma: special reference to malignant and high risk benign meningioma].

Results of radiotherapy in 21 patients who had been treated for intracranial meningioma from April 1975 to March 1993 at Tokyo Metropolitan Komagome Hospital are presented. All patients were treated with 4 MV X-rays using conventional fractionation. The median tumor dose was 54.4 Gy (range 30 Gy to 70 Gy). Radiotherapy was delivered by conformation technique in 11, parallel opposed field in four and three ports technique in two. Of 21 meningiomas, 13 were histologically malignant and 8 were benign. The median follow-up period was 63 months. Overall survival rate at 5 years was 71% for benign and 63% for malignant meningiomas; the 5-year progression-free survival rates were 25% and 30%, respectively. Eight of 21 patients received 60 Gy or more, and the remaining 13 received less than 60 Gy. The 5-year overall survival rates for these two groups were 43% and 83% (p < 0.05), respectively. Ten of 21 patients were treated with post-operative radiotherapy as initial treatment and eleven of 21 patients were treated with salvage therapy with or without surgical excision for recurrent lesions. The 5-year survival rates and progression-free survival rates of these two groups showed no significant differences. From analysis of the clinical course of the salvage therapy group, radiotherapy may prolong survival time and delay further tumor recurrence. According to the present study, radiotherapy (doses of 55 Gy to 60 Gy) after primary resection and at the time of recurrence are equally effective for prolongation of survival and delay of further tumor recurrence.